Acta Cryst. (2008). E64, i78  [ doi:10.1107/S160053680803434X ]

Disodium tricopper(II) tetrakis[selenate(IV)] tetrahydrate

W. Liu, L. Zhang, K. Hu, L. Cao, G. Su and J. Zhao

Abstract: The title compound, Na₂Cu₃(SeO₃)₄(H₂O)₄, has been prepared under hydrothermal conditions. The crystal structure contains a three-dimensional anionic framework made up from distorted [CuO₄(H₂O)₂] octahedra ( symmetry), [CuO₄(H₂O)] square pyramids and trigonal-pyramidal SeO₃ units sharing common corners. The connectivity among these units leads to four- and eight-membered polyhedral rings, which by edge-sharing interconnect into walls. A rhombus-like 16-membered polyhedral ring channel system with a longest length of approximately 14.0 Å and a shortest length of 5.3 Å is enclosed by such walls along the a axis. The water molecules attached to the Cu atoms, as well as the electron lone pairs of the Se^IV atoms, protrude into these channels. The seven-coordinated Na⁺ counter-cations occupy the remaining free space of the 16-membered polyhedral ring channels. An intricate network of O-HO hydrogen bonds further consolidates the three-dimensional structure.

Online 25 October 2008

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